Water is key parameter for the life and the main source of water is ocean in the Earth. Ocean water contained different element, salts, organic and organic compound. If the percentage of composition can be reduced up to limit, it can be used for drinking purpose. The main goal of this study to reduced the hardness, oil and pathogen from the ocean water for better use. Adsorption method was applied to treat the ocean water with the coastal clay. It shown better efficiency at 6 to 8 pH, 4h contact time, 6gm of dosing and heat the clay up to 600C.